


The Devil's Story

by Ena2705



Category: Castle, Lucifer (TV)
Genre: Crossover, Lux (Lucifer TV), Murder, Serial Killers
Language: English
Status: In-Progress
Published: 2018-06-02
Updated: 2019-04-23
Packaged: 2019-05-17 10:53:00
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 4,213
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14830928
Author URL: https://archiveofourown.org/users/Ena2705/pseuds/Ena2705
Summary: When a New York serial killer decides to take a vacation and hit the west coast, the detectives on his case decide to follow suit. Teaming with the LAPD, Castle and Beckett find themselves in a whole new world of nightclubs, corrupt cops, and... the divine?





	1. Let's get this party started

**Author's Note:**

> This is pre-Caskett but don't worry, there will still be some very ship-worthy moments

"Pack your bags Castle, seems like we're going to the city of angels." The phone hung up and Castle didn't need to be told twice. The warm summer days were slowly turning into an autumnal chill in the streets of New York, and he'd happily switch that out for sunny Los Angeles any day. He said his quick goodbyes to his two favourite red heads and was in the cab to the airport. Beckett, of course, was already in the back waiting for him. "So TSA picked up our killer at LAX. We've got in touch with the LAPD and they've asked that since we already know so much about the case, if it would be possible for us to assist them." Castle nodded along to what she was saying, looking at the security photos from the airport in the file that she handed him as he got in. Before long, the pair were soaring above the clouds in what seemed to be the longest plane journey he'd ever taken. He was sure that the sexual tension of them being in such close proximity, all whilst working their case solving mojo, was enough to make the plane take an emergency landing. They finally landed, and as soon as the doors opened, the smell of jet fuel and heat attacked the noses of those in business class. They had arranged for transport to take them straight to the precinct to meet their new temporary team, not expecting the transport to be a luxury limousine, not unlike the ones Castle used to hire before his consultant days. "Wow!" The detective beside him exclaimed, and a sudden pang of jealousy struck Castle in the gut, she never admired anything he bought for her or the precinct but a simple vehicle arranged by someone in the LAPD does.

They walked down the steps into the precinct and were immediately appreciative of the air conditioning in the building, not used to such heat this time of year. "Detective Beckett!" A blonde haired woman called from across the room. They headed to the source of the voice and as they rounded the corner, another man became visible, having previously being blocked from their view by a post. "Hi!" The blonde woman stuck her hand out for his partner to shake. "I'm detective Chloe Decker, this is my partner and civilian consultant for the LAPD, Lucifer Morningstar." The peculiarly named man nodded and smirked in their direction. "Hi detective Decker, I'm Kate Beckett, and this is my partner, who is also a civilian consultant, Richard Castle." Castle shook the detective's hand. "Please, call me Chloe." she said with a smile. Castle had the feeling that she was the type of person that forgives time and time again, so kind hearted but it never wears her down. "Come on, I'll introduce you to the team and then you can go to your hotel, I'm sure you've got jetlag that needs sleeping off." They followed the two Californian partners as Chloe introduced them to Dan, another detective; Ella, the bubbly forensic scientist; and the lieutenant, who Castle could have sworn glared at Lucifer. As Beckett caught Chloe up on the case, Castle thought it a good idea to try to get to know his fellow civilian consultant. 

"So, Lucifer? That's an odd name, if you don't mind me saying."  
"Not at all, Mr. Castle"  
The British accent felt like a smooth whiskey to Castle, and he knew from those first words that he wanted him as a character in his next Nikki Heat novel.  
"What do you do, aside from this."  
"I own a nightclub, and run hell. Part time of course, not enough time to do all that and still enjoy a night of raw sex and a bottle of fine scotch. What about yourself?"  
The mentioning of hell made Castle smile. Either this man was crazy, or he was making light of such an unfortunate name. Either way, he was humorous.   
"Mystery writer. You heard of Nikki Heat? Derek Storm?"  
Lucifer gasped in excitement.  
"You're the author of the Heat series? Oh, I've got to tell Mazikeen, she'll love that! Those sex scenes made even her blush!"  
He reached inside his jacket to grab his phone before pausing.  
"Wait, is Nikki Heat based on your detective Beckett over there? Wow, I should invite her to Lux. You lucky devil!"  
"Well, those particular scenes aren't based on her but yes. Actually that's why I started working with the NYPD. I had connections and decided Kate would be a great inspiration."  
He couldn't help gazing at her fondly as he said that.  
"You like her, don't you?"  
Castle nodded, not wanting to tear his eyes away from Beckett as she dove passionately into the case. Yes, he did.


	2. The Devil's Advocate

They waved goodbye to their new partners and turned to face the murder board. "You got on well with Mr. Castle." The detective mused. "He and I have a lot in common." Lucifer replied, thinking of his own unrequited longing for his partner. "Oh yeah, how so?" Her attention was drawn from the case photos. "Well we both are very well known and admired, with all the right connections in all the right places." He wasn't lying, he just wasn't telling the whole truth. "Beckett was telling me about that, apparently he's just as much of a nuisance as you are." She smirked, knowing how to wind him up. He couldn't help but smile at the sight of joy in her eyes, even if it was at his own expense. As he was about to reply, the detective's spawn came running up to them and tackled his legs with a hug. He wouldn't admit it, but he was getting used to the small child, even growing to like her. "Baby what are you doing here?" Chloe looked at her watch, realizing the time. "Oh my gosh, I'm so sorry monkey. Come on, let's get you home." She took Trixie's hand and headed to the parking lot, not forgetting to turn back to Lucifer and wave goodnight. 

When Lucifer got back to Lux, the night was still young so he decided to stay downstairs for a bit and have a drink. The barmaid who handed him his regular was relatively young, fresh out of college. Lucifer only hired her a couple of weeks ago to replace Maze. Though she still tended the bar from time to time, and mostly just to get in on the action, her appearances were too sporadic and Lucifer needed somebody more regular as his club was getting fuller as each week went by. He was thinking about a Vegas expansion, but that would mean leaving the detective for extended periods of time, something that he promised himself he would never do voluntarily again, not since he saw how much it hurt her last time. He swirled around in his barstool and took a swig of his glass. That night was glitter themed, and the many sparkles reflecting across the room reminded him of his first home: _the mighty silver city_. He needed a distraction, and nothing was a better distraction than a gorgeous body covered in sweat underneath him. Luckily for him, the first person he laid eyes on was simply ravishing. The tight white tee clung to his every toned muscle, his long brown hair practically begging to be stroked and played with. Lucifer finished his drink, not for confidence but simply for the sake of it, and headed towards the first potential partner of the night.

He woke to his phone's alarm the next morning. No, not an alarm, he didn't have an alarm. Slowly rising to consciousness, Lucifer realized that the source of the annoying noise was his phone, and it was the detective calling. "Morning Lucifer, looks like our killer has struck again." He quickly rushed to his dressing room and picked out that day's suit. Daniel often mocked him for wearing a three piece suit in the heat of California, but compared to hell, it was practically freezing. He asked for the address, grabbing his car keys from the table. "No need, just come outside." Dread settled in the pit of his stomach, if somebody was killed at his nightclub, that meant bad press. Dread turned to guilt as he saw the victim sprawled across the pavement, covered in blood. "Vic's been dead for at least 8 hours." Ella speculated, crouched next to the body. "Lucifer, you okay buddy?" She asked when she looked up. That girl was the most caring person he had ever met, and if it ever came to his knowledge that she had somehow ended up in hell, he would personally carry her up to heaven where her soul belonged. "Yes, I-I just know, well, knew this young man." Without even asking permission, the forensic scientist jumped up to give him a hug. When she parted from him, he took in the rest of the scene for the first time. Chloe and Daniel were interviewing potential witnesses, and the new detectives, the ones from the east coast, were ducking under the yellow tape, Mr. Castle handing detective Beckett a takeout cup of what he presumed to be coffee. "Ella, what we got?" The detective asked. As miss Lopez gave her the rundown, Lucifer watched as Castle walked around the body, observing it curiously. "Are those bruises on his neck?" he asked as he circled back to the head. "Love bites, hickeys." Lucifer interrupted Ella before she could get a word out. "If only I could have made him last longer, he might still be alive." He could practically hear Daniel's eyes roll as he approached the group. "Are you saying you slept with the victim last night, Mr. Morningstar?" Detective Beckett asked, stunned. "Of course he did, if there's ever a good looking victim within a 10 mile radius of Lux, it's probably safe to bet that Lucifer has slept with them." Daniel commented, and Lucifer couldn't help but shrug in agreement. 

The signature removed earlobe on the left ear, and the significant closeness to a popular partying place confirmed that this was in fact the same killer that the NYPD detectives were hunting and soon enough they were knee deep in evidence and possible locations of the suspect. Unconsciously, Lucifer kept glancing at the latest photo on the board with his historic building in the background. "I can't believe such an evil being was in my home and I didn't even detect a thing." He hated that another helpless soul fell victim to someone that needed punishing. "We'll catch him, I promise." Detective Beckett tried to comfort him, passing him a coffee. She seemed like a strong, determined woman. Lucifer wasn't good at reading human emotion but he could tell there was a fight behind her, something making her so determined. Curios, he looked her in the eyes and asked: "Tell me, detective, what is it you desire?"  
"I...want to bring justice to victims that was never brought to my mother."  
"Your mother?"  
"She was killed and the cops on the case never found who did it. That was one of the most painful things about her death, and I don't want anyone else to suffer like that."  
"Ah, I see. Well, I'm sure she would be proud of who you became."  
He knew he had spoken those words to Chloe not so long ago, but he had a feeling it was also true for detective Beckett.  
"Thank you, Lucifer. I'm not sure why I told you all that, but thank you."  
Lucifer nodded and turned his attention back to the file in hand, curiosity satisfied and completely oblivious to the imaginative writer now staring at him. He saw Lucifer perform his mojo, and he wanted to know more.

**Notes for the Chapter:**

> Hey, so I know this chapter is a bit longer but it's finally getting into it so I had to elongate it to kick start the story. Thank you for all the immediate positive feedback and I can't wait to write more!


	3. The Story Begins

**Notes for the Chapter:**

> I am so sorry for the late update, college has started again so I haven't had time to write.

“I’m telling you, Ryan! He just looked in her eyes and did some voodoo thing and she told him everything!” Castle was leaning against the wall of the precinct. He had to tell somebody what he saw. After a few more minutes of hushed conversation, Ryan hung up with promise to look into Lucifer Morningstar. Straightening his suit jacket, Castle headed back to the rest of the group. “Catch me up?” he asked, avoiding Lucifer’s gaze and instead focussed his view on his partner. She shot him a questioning glance, asking silently where he had just been. He shrugged her off, she wouldn’t believe him anyway. “Uh, yeah.” Detective Decker replied. “So we believe that instead of scouting at bars as he did back in New York, he’s now hitting up night clubs. You know, ‘new place, new me style’.” It made sense, but back in New York, the killer would go to the same bar two days in a row, teasing the detectives and never getting caught.   
“So that mea-"  
“It means that the scumbag will be back at my home again tonight.”   
Lucifer cut Castle off, rage radiating from him. If he really did believe he was the devil, surely he would admire the evildoings of their killer rather than hating him with such a passion, Castle pondered.

Before long, they had conceived a plan to catch their killer, and it was possibly the most dangerous undercover work Castle had ever done with a police force. All their lives depended on Lucifer’s power of seduction and a woman named Mazikeen, who Castle recalled Lucifer previously mentioning in conversation, but the LA detective and her Lieutenant alike didn’t seem fazed by the plan. Their killer seemed to favour attractive males, and the team decided to use that to their advantage.

“You know,” Lucifer leaned in closer to Castle. “It could be a religious thing.” Castle turned towards him and indicated for him to continue. Lucifer instead reached behind the bar to pull out a bottle of scotch. After filling his glass and offering one to Castle, which he accepted, Lucifer proceeded. “Well, a few thousand years ago, way before your people created their little fairy tales about my half-brother, which aren’t true by the way, he was actually a major dick. Boring as hell too, couldn’t take a joke. Anyway, years before that, I got tired of the same old, same old religious sacrifices making their way downstairs so I went up and spread a few rumours here and there. You know, ‘God condemns all people with ginger hair, sacrifices must have three boobs, etcetera etcetera. However, my personal favourite was that if someone is sacrificed, the devil would bite them by their left ear and drag them to hell. I wouldn’t, of course, but it was quite hilarious watching people come down earless. Actually, you might have heard of one person…Van Gough? He wasn’t a human sacrifice but I guess he didn’t want to tempt fate.” This man sure knew how to make a story. “Maybe he is sacrificing promiscuous young men.” For as immature as Mr. Morningstar made out to be, he did have a point. Castle made a mental note to look down that route if they didn’t catch the killer that night. 

The elevator pinged and the doors slid open, revealing a beautiful woman stood with her head held high and holding a knife. “Uh… Lucifer?” Castle asked, stepping back. However, when he looked at the man stood next to him, he didn’t look afraid. “Maze!” Lucifer greeted her with a smile on his face. The woman, who he now knew to be the aforementioned Mazikeen stepped out the elevator and down the stairs with a confidence very few can pull off. She must have noticed the worry on Castle’s face, or his constant monitoring of her blades as she approached them because she swung them round a few times before tucking them in the waistband at the back of her leather pants. At least, that’s where he hoped she had put them, but with what he saw Lucifer doing earlier, he wouldn’t be surprised if they vanished into thin air. Mazikeen finally reached where the two men were standing and inched towards Castle until his back was against the cool metal bar and he couldn’t escape any further back. Maintaining eye contact with him, she moved around him and lent over the counter to produce her own glass, poured herself a drink and edged away from him, smirking over the fact that she had intimidated him. 

Lucifer Morningstar had sat down with his scary friend to discuss details of the plan when Castle’s phone rang. The flashing image showed Ryan’s face, a photograph taken from last year’s alcohol fuelled Christmas party, one which the detective begged him to change but Castle insisted it was just too funny. He excuses himself from the room and headed to the men’s bathroom, not wanting either of the pair to overhear the conversation and risk being stabbed with one of Mazikeen’s blades.   
“Hey, Ryan. What you got?” he whispered.   
“Well it’s strange, really. Looks like Lucifer Morningstar just appeared one day out of the blue 6 years ago, his friend Mazikeen Smith doing so too. According to police files and witness statements, though the primary witness always seems t be his partner Chloe Decker, he has been shot, burnt and stabbed many times yet remains alive.”  
“Wow, lucky guy!” Rather, he should say unlucky.   
“Yeah, strangest part is, however, from photos taken by partygoers or fans, he doesn’t have a single scar from these incidences. The only ones he has, I can’t find a history of.”  
Castle must have paused for a moment in thought.   
“Castle, you still there?”  
“Yeah, I’m still here.”  
“I’ve got to go now, me and Espo have a case. But be careful, man. This guy seems dangerous. He has connections with several mafias and drug lords.”

Castle hung up and thought: ‘A potential criminal, working for the LAPD. This would make for a great story.’


	4. Chapter 4

Lucifer had always been a fan of themed nights at Lux. It meant that he could get ever more creative with the guests he brought upstairs because of their costume props. Sipping on a fresh bourbon and scanning the dance floor, he reminisced on a pirate themed night, and the subsequent orgy-of which the hooks, eye patches, and plastic swords came in very handy. Tonight’s theme, however, was nowhere near as fun. Wet t-shirt contest. How mundane.   
As Mr Castle returned to the bar, a spurt of foam landed on the ever growing pile that people were dancing amongst. “Okay guys, Dan is coming down the stairs now. Maze, remember to not lose sight of him, he’s unarmed.” Came the detective’s voice in Lucifer’s ear. “Yeah, yeah Decker. I got it.” The leather clad demon replied. Maze may be in on the operation, but she refused to wear something as un-sexy as a plain white tee.   
Promptly, Douche walked down the stairs to the dancefloor, and his thin cotton tee got instantly soaked from the foam; material clinging to his muscular form. Lucifer raised his glass to Mr Castle, before swinging it back and getting ready to mingle with the crowd. 

The plan was simple enough: Lucifer obnoxiously flirted with Daniel in hopes of catching the serial killer’s attention, before bringing him up to the penthouse. After a few hours, Dan was to leave looking much scruffier and post-sex like than when he came in, and see if the killer would corner him, with a squad of black and whites waiting to pounce. Maze was there to act as Douche’s security throughout the night, and Mr Castle was to sit at the bar the whole night and try to spot the “party pooper”, as the media deemed the culprit. 

Lucifer saw no problem with the plan, but his fellow smitten consultant voiced his worries that an officer was going in unarmed, his only protection being a knife-clad civilian. Oh if only he knew the damage Mazikeen could inflict.   
The night was getting into full swing, and as much as Lucifer hated getting one of his precious suits wet, he must admit, it made everyone else look positively delicious. Deeming the place full enough, detective Beckett gave Lucifer the go ahead to focus his attention on Dan. 

“Why hello, sexy. Tell me dear, what’s your name?” Daniel surpressed a shudder at Lucifer’s directed flirting. “Wouldn’t you like to know.” Lucifer smirked, and pressing a hand against Douche’s side, he pressed once more for his name. “Oh please, just give me this. You are dancing under my roof, after all.” Lucifer heard the detective mutter to Beckett that it was very weird watching her partner flirt with her ex, and Beckett laughing in retort in his earpiece. “Oh you own this place? Well then I guess my name is Cal.” Dan put on a fake smile. “Callll” Lucifer purred. 

A few hours later, and the operation had proved unsuccessful, the perp never showed, and Lucifer had ruined a suit for naught. He made sure to voice this complain too. Nobody seemed to pay attention to his moaning though. He retrospectively noted that this may have been because they were stood over another body at the time. 

“I don’t get it. Why is he breaking the pattern? He should have been at Lux again, not this place.” Ella voiced in the forensics lab as they gathered round to look at some evidence. “He could be taunting us, making us chase him. A game.” That, for Lucifer, was a worrying thought. If this bastard was sick enough to be taunting the police with no concern, how much longer would he be killing, and would he feel guilty enough for punishment when he died?


	5. Chapter 5

Castle yawned as he walked into the station the next day; he hadn't got much sleep because Beckett was pacing the room all night. He didn't blame her though, they had been chasing this guy for almost 4 months and just as he seemed close, he taunted them once again. He set the tray of coffees down on detective Decker's desk, having bought enough for all four of them, and headed to the break room to see what he could raid from the vending machine, hoping it would have better quality content than the one at the 12th precinct. As Castle walked in, he saw Lucifer sat at the table in the center of the room, talking on the phone. 

"I want security cameras on every wall, every alley way along Lux. I don't want a single blindspot.  
No, I'm not concerned for my safety, I don't get hurt.  
…  
Look, I don't care how much it is going to cost. A man was murdered outside MY club, and I don't want it to happen again.  
First there was my dear friend Delilah, and now a patron on my nightclub. It's bad for business and people will stop attending.  
I want extra bouncers until the police arrest this man. Every night.  
Goodbye."

Castle stood quietly in the corner and watched as Lucifer sighed and rubbed his hands over his face, pondering over what the consultant said. _Delilah? Invulnerability? This is sure one interesting character._ Castle sniffed to alert Lucifer of his presence, and pulled a seat up next to him.  
  
"Trust me, I know exactly how you're feeling." He started.  
  
Lucifer turned his head slightly towards Castle. "You do?"  
  
"His first, and second, attack was outside my bar."  
  
"Your bar? I thought you were an author."  
  
Castle stopped himself from correcting Lucifer, he wasn't just an author, he was a bestselling mystery novelist (with film adaptation). "The Old Haunt, you should swing by next time you're in town. It's quite the historic building."  
  
Lucifer nodded. "And what did you do?"  
  
"The same as you just did, and became determined to catch the guy that stained the steps."  
  
He didn't know if his advice was of any help to Lucifer, as he turned his head away and shut his eyes. Castle stood up and headed in his original direction towards the vending machine.  
"The mini donuts are stale." Came a smooth British accent from behind him. Castle smirked.

"There you boys are!" Beckett declaired as the two consultants headed towards detective Decker's desk, smacking a case file down on the desk. Castle noted the aforementioned detective checking her gun and tying her hair up. "Come on, a plain clothed officer spotted our perp from the pictures TSA gave us at a coffee shop. He went to pull his gun but the perp has taken the whole building hostage, knocked him out." Castle was somewhat relieved to hear that this was almost over, but the concern for the hostages overwhelmed that.  
"We'll take two cars so he can take a ride in the back after you make the arrest." Beckett said to detective Decker. Castle knew that as much as Beckett wanted to be the one to slap the cuffs on, it was out of her jurisdiction and she wouldn't do anything to compromise the legal process. the LAPD detective agreed with what she said and added: "follow behind us, you don't know the area." And with that, they were jogging down to the parking lot. This nightmare might nearly be over, but of course it couldn't end without a showdown.


End file.
